diff options
Diffstat (limited to 'src/libsystemd-bus/bus-bloom.c')
| -rw-r--r-- | src/libsystemd-bus/bus-bloom.c | 20 |
1 files changed, 12 insertions, 8 deletions
diff --git a/src/libsystemd-bus/bus-bloom.c b/src/libsystemd-bus/bus-bloom.c index c3ad9f6385..9e51334b52 100644 --- a/src/libsystemd-bus/bus-bloom.c +++ b/src/libsystemd-bus/bus-bloom.c @@ -20,16 +20,18 @@ ***/ #include "util.h" -#include "MurmurHash3.h" - +#include "siphash24.h" #include "bus-bloom.h" static inline void set_bit(uint64_t filter[], unsigned b) { filter[b >> 6] |= 1ULL << (b & 63); } +#define HASH_KEY1 SD_ID128_MAKE(b9,66,0b,f0,46,70,47,c1,88,75,c4,9c,54,b9,bd,15) +#define HASH_KEY2 SD_ID128_MAKE(aa,a1,54,a2,e0,71,4b,39,bf,e1,dd,2e,9f,c5,4a,3b) + static void bloom_add_data(uint64_t filter[BLOOM_SIZE/8], const void *data, size_t n) { - uint16_t hash[8]; + uint8_t a[8], b[8]; unsigned k = 0; /* @@ -38,17 +40,19 @@ static void bloom_add_data(uint64_t filter[BLOOM_SIZE/8], const void *data, size * m=512 (bits in the filter) * k=8 (hash functions) * - * We calculate a single 128bit MurmurHash value of which we - * use 8 parts of 9 bits as individual hash functions. + * We calculate a two 64bit SipHash values (for two fixed but + * randomly generated hash keys) of which we use 8 parts of 9 bits + * as individual hash functions. * */ - MurmurHash3_x64_128(data, n, 0, hash); + siphash24(a, data, n, HASH_KEY1.bytes); + siphash24(b, data, n, HASH_KEY2.bytes); assert_cc(BLOOM_SIZE*8 == 512); - for (k = 0; k < ELEMENTSOF(hash); k++) - set_bit(filter, hash[k] & 511); + for (k = 0; k < 8; k++) + set_bit(filter, ((uint16_t) a[k] << 1) ^ (uint16_t) b[k]); /* log_debug("bloom: adding <%.*s>", (int) n, (char*) data); */ } |